1. Field of the Invention
The present invention relates generally to thermal management in electronic applications and, more specifically, to thermal conductors incorporating electromagnetic-energy-attenuating properties.
2. Description of the Prior Art
As used herein, the term EMI should be considered to refer generally to both electromagnetic interference and radio-frequency-interference (RFI) emissions, and the term “electromagnetic” should be considered to refer generally to electromagnetic and radio frequency.
Electronic devices typically generate thermal emissions as an unavoidable byproduct. The amount of thermal emissions generated can correlate to the switching speed and complexity of the source electronic component or device. As newer electronic devices tend to operate at greater and greater switching speeds, they will also result in greater thermal emissions. These increased thermal emissions, at some level, pose a risk of interfering with the function of the source electronic component, and with the functions of other nearby devices and components.
Accordingly, the unwanted thermal emissions should be dissipated benignly to preclude or minimize any undesirable effects. Prior-art solutions addressing the removal of unwanted thermal emissions include providing a thermal pad over the electronic component and attaching a heat sink to the thermal pad. Heat sinks generally include material with high thermal conductivity. When placed in intimate contact with a heat-generating electronic component, the heat sink conducts thermal energy away from the component. Heat sinks also include attributes that facilitate heat transfer from the heat sink to the ambient environment, for example, through convection. For example, heat sinks often include “fins” that result in a relatively large surface area for a given volume.
Furthermore, under normal operation, electronic equipment typically generates undesirable electromagnetic energy that can interfere with the operation of proximately located electronic equipment due to EMI transmission by radiation and conduction. The electromagnetic energy can exist over a wide range of wavelengths and frequencies. To minimize problems associated with EMI, sources of undesirable electromagnetic energy can be shielded and electrically grounded to reduce emissions into the surrounding environment. Alternatively, or additionally, susceptors of EMI can be similarly shielded and electrically grounded to protect them from EMI within the surrounding environment. Accordingly, shielding is designed to prevent both ingress and egress of electromagnetic energy relative to a barrier, a housing, or other enclosure in which the electronic equipment is disposed.
Sound EMI design principles recommend that EMI be treated as near as possible to the source to preclude entry of unwanted EMI into the local environment, thereby minimizing the risk of interference. Unfortunately, components and devices requiring the use of heat sinks are not well suited for protective treatment for EMI at the source, because such treatment would interfere with the operation of the heat sink. The heat sink should be in intimate contact with the electronic component to provide a thermal conduction path and also be open to the surrounding environment to allow for the heat sink to function through convective heat transfer.